Line indicator for typewriter platens

ABSTRACT

A TYPEWRITER PLATEN HAS A CARD INDICATOR CONNECTED THERETO WHICH INCLUDES A DETENT RING HAVING A SINGLE DETENT NOTCH IN ITS PERIPHERY WHICH IS SENSED DURING PLATEN ROTATION BY A DETENT ROLLER MOUNTED ON THE CARRIAGE. THE DETENT RING, FOR THE PURPOSE OF RELATIVE ROTATIONAL ADJUSTMENT OF THE DETENT RING AND CARD CLAMP, IS MADE ROTATABLE INDEPENDENTLY OF THE PLATEN BY MOUNTING IT ON THE LINE SPACING RATCHET FOR ROTATION WITH THE LATTER. RELEASE OF A LINE SPACING RATCHET CLUTCH PERMITS THE ROTATION OF THE PLATEN WITHOUT AFFECTING THE LINE SPACING RATCHET AND THE DETENT RING, ALLOWING THE NOTCH IN THE LATTER TO BE FIRST ROTATED INTO DETENTED POSITION AS THE PLATEN IS TORATED AND THE SUBQUENT ROTATION OF THE PLATEN AND CARD CLAMPING BAR ALONE TO A DESIRED LINE POSITION. WHENEVER, THEREAFTER, THE DETENT ROLLER ENTERS THE DETENT NOTCH, IT WILL BE AN INDICATION TO THE OPERATOR THAT A PREDETERMINED LINE OF CARD HELD BY THE CARD CLAMP IS IN PROPER TYPING POSITION. THE ADDITIONAL TORQUE PROVIDED BY REGISTRATION OF THE DETENT AND DETENT NOTCH, WHILE PRODUCING A CLEAR SIGNAL THAT A DESIRED LINE POSITION HAS BEEN REACHED, IS NOT SUFFICIENT TO INTERFERE WITH SUBSEQUENT CONVENTIONAL LINE FEED FUNCTIONS. THE DETENT ROLLER IS MOUNTED ON A PIVOTED, SPRING-BIASED BELLCRANK CARRIED BY THE CARRIAGE. A LATCH FINGER AT ONE END OF THE BELLCRANK CAN BE SWUNG INTO CONTACT WITH THE CARRIAGE FRAME TO DISABLE THE DETENT ROLLER.

Sept. 1971 HUGH sT. LAWRENCE DANNATT 3,505,979

LINE INDICATOR FOR TYPEWRITER PLATE-NS Original Filed April 27, 1967 3Sheets-Sheet 1 "IHII l4 I2 '0 l.

88 g 8 3 J5 :1: 9 I I Q L m w I m m (O 2 mvmron. Q HUGH ST. LAWRENCEDANNATT v v g v.9 7 I" 1 l 4" u [\n AGENT Sept; i971 HUGH ST. LAWRENCEDANNATT 3,605,979

LINE INDICATOR FOR TYPEWRITER PLATENS Original Filed April 27, 1967 3Sheets-Sheet 2 QZW IIVWIEM mm wwom 7 67/ 1 i UH A i. Q

I. .8 wk

W N 1:: 0 @N::

mm 3 mm m w mll n p 1971 HUGH s'r. LAWRENCE DANNATT 3,505,979

LINE INDICATOR FOR TYPEWRITER PLATENS Original Filed April 27, 1967 3Sheets-Sheet 3 Tac 1. 85 84 I06 62 I2 I24 I13 86 I22 I50 I L Hh 0 n4 Ill8 u; no

so 74 9s 92 United States Patent O 3,605,979 LINE INDICATOR FORTYPEWRITER PLATENS Hugh St. Lawrence Dannatt, Rochester, N.Y., assignorto The Singer Company Original application Apr. 27, 1967, Ser. No.634,223, now Patent No. 3,474,889, dated Oct. 28, 1969. Divided and thisapplication Oct. 30, 1968, Ser. No. 798,236 Int. Cl. B411 29/42 US. Cl.197-187 2 Claims ABSTRACT OF THE DISCLOSURE A typewriter platen has acard line indicator connected thereto which includes a detent ringhaving a single detent notch in its periphery which is sensed duringplaten rotation by a detent roller mounted on the carriage. The detentring, for the purpose of relative rotational adjustment of the detentring and card clamp, is made rotatable independently of the platen bymounting it on the line spacing ratchet for rotation with the latter.Release of a line spacing ratchet clutch permits the rotation of theplaten without affecting the line spacing ratchet and the detent ring,allowing the notch in the latter to be first rotated into detentedposition as the platen is rotated and the subsequent rotation of theplaten and card clamping bar alone to a desired line position. Whenever,thereafter, the detent roller enters the detent notch, it will be anindication to the operator that a predetermined line of a card held bythe card clamp is in proper typing position. The additional torqueprovided by registration of the detent and detent notch, while producinga clear signal that a desired line position has been reached, is notsufficient to interfere with subsequent conventional line feedfunctions.

The detent roller is mounted on a pivoted, spring-biased, bellcrankcarried by the carriage. A latch finger at one end of the bellcrank canbe swung into Contact with the carriage frame to disable the detentroller.

CROSS REFERENCE TO RELATED APPLICATION This is a division of copendingU.S. patent application Ser. No. 634,223, filed Apr. 27, 1967, nowissued as US. Patent No. 3,474,889, on Oct. 28, 1969, to Hugh St.Lawrence Dannatt.

BACKGROUND OF THE INVENTION The invention relates to typewritingmachines and particularly to a printing line indicator associatedtherewith.

Card holding clamps for typewriter platens are well known.

A new and improved card holding clamp is disclosed in theabove-identified copending application. Card holding clamps arefrequently used when it is desired to type on relatively short forms ordocuments which cannot be held in position on the platen by the usualdocument holding means. In such applications it is not unusual torequire that the typing start a predetermined distance from the end ofthe form. The present invention provides a convenient means for rapidlypositioning such a short form on the platen of a typewriter so thattyping may begin at any desired predetermined position relative to oneend thereof.

It is the primary purpose of the invention to provide a convenient meansfor positioning forms on a typewriter platen so that the initial line oftyping may be started a predetermined distance from the end of thedocument. It is a more specific object of the invention to provide anauxiliary detent ring and detent for use with a typewriter platenequipped with a card clamping bar and the usual line indexing ratchet,pawl, and detent for providing an 3,605,979 Patented Sept. 20, 1971indication when the platen is at a predetermined and adjustable angle ofrotation relative to a reference.

BRIEF DESCRIPTION OF THE DRAWING The purpose of the invention and itsadvantages, will be more fully understood by reference to the drawingwhich illustrates a presently preferred embodiment, when viewed in lightof the detailed description to follow. In the drawing, like referencenumerals indicate like parts, and:

FIG. 1 is an external plan view of a typewriter platen in which theimprovements comprising the present invention are embodied;

FIG. 2 is an external foreshortened elevational view of the platen ofFIG. 1 on a somewhat enlarged scale and showing in conjunction therewithrelated elements of a typewriter carriage;

FIG. 3 is a longitudinal sectional view on line 33 of FIG. 1, showingthe parts thereof in a repose;

FIG. 4 is a view corresponding to that of FIG. 3 showing, however, theparts thereof operated into clamping bar release position;

FIG. 5 is a transverse cross-sectional view on line 5-5 of FIG. 3;

FIG. 6 is a transverse cross-sectional view on line 66 of FIG. 4;

FIG. 7 is a detail on line 77 of FIG. 4;

FIG. 8 is a transverse section on line 8 8 of FIG. 2 showing elementsthereof in full line and certain detent mechanism in inoperativeposition;

FIG. 9 is a transverse section similar to that of FIG. 8 showing,however, the detent mechanism in operative FIG. 10 is a transversesectional view on line 1010 position; of FIG. 2 showing parts in fullline and illustrating particularly the mechanism associated with a linespacing ratchet; and

FIG. 11 is a longitudinal sectional view on line 1111 of FIG. 9 showingparts of the left end of the platen mechanism.

The card clamping bar in association with a typewriter platen is shownin FIGS. 1-6 while its associated operating mechanism comprising aprincipal feature of the invention is best shown in FIGS. 3 and 4,wherein a conventional rubber covered platen 10 has mounted thereon acard clamping bar 12. The card clamping bar 12, as best seen in FIGS. 5and 6, is mounted on a flat surface 14 of the platen 10 and the bar 12itself, as shown in these latter views, has an arcuate upper face 16which is ideally a continuation of the circumference of the platen 10.

The clamping bar 12 is operatively associated with the platen 10 bymeans of a plurality of guide studs 18 which operate through the platen10 wall and extend to the interior of the platen 10 where they areconnected to an operating bar 20. The operating bar 20 is mounted forradial movement in a guide frame 22 fixed radially within the platen 10.The clamping bar 12 is normally held in firm contact with the face ofthe platen 10 by means of a plurality of coil springs 24 having one endthereof connected to the operating bar 20 and the other end to the baseof the guide frame 22. These springs 24 are so proportioned that theoperating bar 20 is drawn toward the base of the guide frame 22 to anextent sufiicient to hold the clamping bar 12 against the surface of theplaten 10.

When it is desired to release the clamping bar 12 into the positionshown in FIG. 4, such release is conveniently effected by manipulating aplurality of toggle levers 26 which are pivoted at their respective endsto the operating bar 20 and the guide frame 22. An intermediate pivot 28of the toggle levers 26 is connected to a clamp actuating shaft 30 whichextends along the axis of the platen 10.

The clamp actuating shaft 30 (see FIG. 7) terminates at its right end ina yoke 32 which straddles the guide frame 22 and provides a connectionfor a clamping bar release cable 34. The clamping bar release cable 34is threaded through a right end platen shaft 36, and therebeyond it isconnected to a clamp bar release knob 38. The distal end of the clampbar release cable 34 is attached to a cable connector 40 (FIG. 3) whichextends through the shank of the cable bar release knob 38 where itsscrewthreaded end in conjunction with a cable tension adjusting nut 42permits minor adjustments in cable tension.

At this point, it can be seen that if the cable bar release knob 38 ispulled to the right in an axial direction, the clamp actuating shaft 30will spread the toggle levers 26 with the result that the operating bar20 is moved outwardly along the radius of the platen and the clampingbar 12 is released. However, since such axial movement of the clamp barrelease knob 38 is inconvenient and affords no advantage over the priorart devices, the clamp bar release knob 38 is arranged in joy stickfashion, so that a mere lateral deflection of the knob 38 at anyconvenient angle will result in the release of the clamping bar 12. Tothis end, the release knob 38 is connected to the platen 10 by afulcrumed joint arrangement. Conceptionally, the connection between thetwo may be in the form of a modified ball and socket joint which hasmeans permitting a relative separation of the ball and socket to applyan axial force to the clamping bar release cable 34, or, as specificallyshown in FIGS. 3 and 4 in the form of a disk operating in a cup, withoutparticular regard to which of the elements of the joint are on therelease knob 38 or on the platen 10. The cup and disk connection hasbeen selected for illustration and specific description as a preferredembodiment by which the invention may be disclosed advantageously.

In a specific form of the invention here selected for purpose ofillustration, the clamping bar release knob 38 has formed therein acavity forming a cup which provides an annular rib 44 (see FIGS. 3 and4) adapted to cooperate with a clutch disk 46. The clutch disk 46 has anannular groove 48 (see FIG. 4) therein, defined in part by an annularlip 50 adapted to mate with the annular rib 44. The annular rib 44, incombination with the annular lip 50, constitute a species of jointswhich permit a to deflection of the clamp bar release knob 38 in anydirection in reference to the axis of the platen 10. This relationshipand coaction is shown in FIG. 4. When the clamp bar release knob 38 isdeflected in any convenient direction, a point along the annular rib 44and a point on the annular lip 50 coact as a fulcrum about which therelease knob 38 may pivot, thereby pulling the clamping bar releasecable 34 outwardly and thereby operating the toggle mechanism 26 torelease the clamping bar 12.

The clutch disk 46 is formed with an axial hub 52 adapted to fit aboutthe outer end of the right end platen shaft 36 to which it is attachedby means of a set screw 54. The conventional bearing sleeve 59 by whichthe right end of the platen 10 is mounted in the carriage (not shown) isinterposed between the inner end of the axial hub 52 and the adjacentend of the platen 10.

Extending outwardly from the clutch disk 46 are a plurality of drivepins 56 which are adapted to enter respective drive pin sockets 58formed in a clutch plug 60 seated in a minor cavity defined in part bythe annular rib 44 of the clamp bar release knob 38. Thus, when in itsnormal operative position as shown in FIG. 3, the clamp bar release knob38 will be securely connected to the right end platen shaft 36 throughthe drive pin sockets 58, the drive pins 56 and the axial hub 52.

A suflicient number of drive pins 56 are provided, preferably equallyspaced about the clutch disk 46, so that one or more are always engagedwith their respective drive pin sockets 58, without respect to the angleat which the release knob 38 is deflected. So arranged, the platen 10can be rotated even though the release knob 38 is deflected. The clutchpins 56 are securely bonded to the clutch disk 46, and the clutch plug60, which is preferably made of rubber or other suitable resilientmaterial, is firmly secured in the base of the clamp bar release knob38.

It should now be evident that operation of the clamping bar 12 into itsrelease position completely eliminates the necessity for generallyunnatural motions such as the application of either axial or radialforces as in the prior art, but that its operation can be accomplishedby the completely natural deflection of the clamp bar release knob 38 inany convenient direction. Upon such deflection, the clamping bar releasecable 34 will be pulled outwardly with the result that the clampactuating shaft 30 will follow its movement. Such movement of the clampactuating shaft 30 will spread the toggle levers 26 thus moving theoperating bar 20, its attached guide studs 18, and the clamping bar 12outwardly into the position illustrated in FIGS. 4 and 6. Upon releaseof the clamp bar release knob 38, it will spring back to its normalposition since the clamping bar release cable 34 is under tension byreason of the springs 24. All the drive pins 56 will re-engage the drivepin sockets 58, so that rotation of the clamp bar release knob 38 willeffectively rotate the platen 10 during normal platen indexingoperation. Concurrently, the return springs 24 will draw the operatingbar 20 inwardly toward the axis of the platen 10 with the result thatthe clamping bar 12 will be in clamping contact with the face of theplaten 10.

Preferably, the platen 10 is also provided with card stops 62 and 64attached to the face of the platen 10 in axial alignment with theclamping bar 12. Such stops 62, 64- are useful in the lateralpositioning of the cards (not shown) upon which typing is to be done.The stops 62 and 64 serve as the conventional paper guide found in alltypewriter carriages. The position of the card stops 62, 64 may beadjusted by reason of an oblong slot 66 therein provided for anattaching screw '68. The card stops 62 and 64 can be shifted in an axialdirection simply by backing off their attaching screws 68 and moving thestops 62 and 64 as required and permitted by the oblong slot 66.

In connection with a card clamp arrangement for typewriter platens, itis highly desirable to provide some means for conveniently locating thefirst line of the card on which typing is to be performed. Devices forthis purpose have been heretofore suggested as in the J.A.B. Smith U.S.Pat. 2,272,098. The arrangement for that purpose herein providedcomprises an improvement over the prior patents. The mechanism involvedin this feature of the invention is best shown in FIGS. 8-11.

In FIG. 10 of the drawing is shown a conventional line spacing ratchet70 in conjunction with its detent 72 mounted on a ratchet detent arm 74which is mounted on the carriage structure. The detent arm 74 is biasedagainst the ratchet teeth 76 by a ratchet detent spring 78 coiled aboutthe detent arm pivot screw 80 and having one end 78a connected to theratchet detent arm 74 and its other end 7812 in abutment with thecarriage base 82.

The line spacing ratchet '70 herein has been modified to accommodate adetent ring 84 (see FIGS. 9 and 11) seated on an inwardly projectingflange 86 (FIG. 11) formed on the conventional line spacing ratchet 70.The detent ring 84 at one point in its circumference, as shown in FIGS.8 and 9, has formed therein a single detent notch 88 which cooperateswith a detent roller 90 also mounted on the carriage structure. When thedetent roller 90 enters the detent notch 88 as the platen 10 is rotated,it serves as a signal to the operator that the platen 10 has beenrotated to a predetermined position which may correspond to the firstline of typing on the card being processed. The signal comprises both anaudible click when the detent 90 enters the detent notch 88 andincreases the torque required to produce further rotation of the platenuntil the detent 90 and the detent notch 88 are disengaged from eachother.

The detent roller 90 is carried by a detent arm 92 mounted for rockingmovement on a pivot sleeve 94 (FIG. 11). This sleeve 94 is supportedfrom the end frame of the carriage by the detent arm pivot screw 80. Thedetent arm 92 is formed with a hub 96 assembled in bearing relationshipto the sleeve 94 for free rocking motion thereon. The detent arm 92,however, is urged toward the detent ring 84 by means of a detent spring98 which is coiled about the hub 96 and having one end connected to thedetent arm 92 and the other end in contact with the carriage base 82 ina fashion similar to the corresponding spring 78 which biases theratchet detent arm 74.

It will become highly desirable from time to time as, for example, whenusing a conventional platen to disable the detent roller 90. Providingan arrangement for this purpose is a depending detent latch arm 100(FIGS. 8 and 9) to the end of which is pivoted a detent latch 102. Thelatch arm 100 has a laterally extending latch stop 104. In the operativeposition of the detent arm 92, the latch 102 is manually rotated intocontact with the latch stop 104 where it will rest, as shown in FIG. 9.When it is desired to disable the detent roller 90, the detent arm 92 ismanually rotated in a counterclockwise direction, as shown in FIG. 8,where it is held in the retracted position by abutment of the detentlatch 102 with the carriage base 82.

It should be mentioned that when the detent ring 84 is mounted on theline spacing ratchet 70, the relative rotational position of the twoelements 70, 84 must be adjusted to put them in phase with theirrespective detent rollers 90 and 72. That is to say, before the positionof the detent ring 84 is fixed with respect to the ratchet 70, it shouldbe ascertained that the ratchet detent 72 is seated properly and fullyin one of the ratchet teeth 76 while at the same time the detent roller90 is also properly and fully seated in the detent notch 88 of thedetent ring 84. When this rotational position is reached, a plurality ofcircumferentially spaced set screws 85 in the detent ring 84 are screweddown against the flange 86 of the line spacing ratchet 70. This servesto lock the detent ring 84 to the line space ratchet 70 so that the twowill rotate together with no relative rotation between them. The twowill remain in phase and require no further adjustment.

It is contemplated that the feature may be usefully employed for typingcards within a wide range of lengths. Therefore, to condition the platen10 for the processing of cards of any given size, the platen 10 and linespacing ratchet 70 are rotated until the detent roller 90 falls into thedetent notch 88. The platen 10 is now released from its line spacingratchet-detent ring assembly 70 and is independently rotatable until thecard clamp 12 is in the proper position to present the selected line ofa card held thereby at the line typing position. After this position hasbeen reached, the line spacing ratchet-detent ring assembly 70, 84 isagain connected with the platen 10 for simultaneous rotation upon normalline spacing operation of the platen 10.

The mechanism provided for this purpose is largely conventional and isshown in FIGS. 10 and 11. The left end of the platen 10 has fixedthereto an end block 106 which extends into the platen 10 and has anexterior surface on which the line spacing ratchet-detent ring assembly70, 84 is rotatably mounted. The end block 106 has an outwardly openingaxial cavity 107. A tubular platen hub 108, having a radial platen endplate 110 at its inner end, is attached to the end block 106 by means ofa plurality of screws 113 which extend through the platen end plate 110and into the end block 106.

A ratchet release shaft 112 is mounted in the platen hub 108 for limitedaxial movement therein. The outer end of the ratchet release shaft 112has a ratchet release button 114 attached thereto by which the ratchetrelease shaft 112 may be pressed inwardly. The axial cavity 107 of theend block 106 accommodates the inner end of the ratchet release shaft112, a clutch bar 116, and a clutch spring 118 which is interposedbetween the inner end of the ratchet release shaft 112 and the innerwall of the end block cavity 107. The face of the end block 106, as bestseen in FIG. 10, is slotted to accommodate the outer ends of the clutchbar 116 which extend through these slots and have formed in the endfaces thereof clutch bar teeth 120 and which are normally in engagementwith similar teeth 122 formed on the inner face of the annuluscomprising the line spacing ratchet 70. From the foregoing, it can beseen that when the ratchet release shaft 112 is in its normal position,as shown in FIG. 11, and the clutch bar teeth 120 are in engagement withthe internal teeth 122 of the line spacing ratchet 70, rotation of theplaten knob 124 will cause rotation both of the platen 10 and the linespacing ratchet-detent ring assembly 70, 84. Torque for rotation of theplaten 10 is transmitted from the platen knob 124 through the platen hub108 by reason of a spline connection comprising setscrew 150 between theknob 124 and the hub 108. The end block 1106 in turn rotates the clutchbar 116 whose teeth 120 normally engage the internal teeth 122 of theline spacing ratchet 70.

When the ratchet release button 114 is depressed against the tension ofthe clutch spring 118, the clutch bar 116 will be moved deeper into theend block cavity 107 and the clutch will thereby be disengaged from theline spacing ratchet-detent ring assembly 70, 84. The disengagementresults from the fact that the clutch bar 116 and its teeth 120 aremoved inwardly to a point at which the clutch bar 116 and the ratchetare no longer in driving engagement. Rotation of the platen tknob 124will now rotate the platen 10 without an accompanying positive rotationof the line spacing ratchet-detent ring assembly 70, 84.

When it is desired to condition the platen 10 for the typing of cards ofa given size and on a predetermined initial line, the platen knob 124,in its normal position, will be rotated with the resulting rotation ofthe platen 10 and line spacing ratchet-detent ring assembly 70, 84 untilthe card clamp 12 is accessible at the front of the carriage. Thereuponthe card clamp 12 is released as previously described, and one edge of acard, shown in dot-dash line C in FIG. 6, is engaged under the cardclamp 12. Rotation is resumed until the detent roller falls into thedetent notch 88. At this point, the ratchet release button 114 isdepressed, as above described, releasing the line spacing ratchet-detentring assembly 70, '84, and the platen 10 alone is further rotated untilthe selected line on the card registers with the line typing position ofthe typewriter. The ratchet release button 114 is then released, theclutch bar 116 is thereby reengaged with the teeth 122 of the ratchet 70under the influence of the spring 118, and the machine is nowconditioned for the subsequent typing of additional cards of the samesize and line configuration without further adjustment. Thereafter, whena blank card is engaged under the card clamp 12, the platen 10 and linespacing ratchet-detent ring assembly 70, 84 are rotated as a unit untilthe detent roller 90 falls into the detent notch 88 which is a signal tothe operator that the card is now properly positioned for typing of thefirst line.

It should be noted that the clutch teeth and 122 are relatively smallcompared to the ratchet teeth 76. This permits the very fine rotationaladjustment of the platen .10 after the detent roller 90 and the detentnotch 88 have been engaged with each other.

From the foregoing, it can be seen that the card clamp and the lineindicator operate in concert to provide a pair of reference points whichgreatly facilitate the registration of any selected line of a card atthe type line of 8 a typewriter, thereby speeding the card typingoperation for movement toward and away from said platen, and far beyondthat which Would be possible without these the other end of saidbellcran-k has a latch thereon for aids. latching said bellcrank againstmovement about its pivot What is claimed is: when said second detentroller has been moved away 1. A character by character printercomprising: from said platen. '(a) a document supporting cylindricalplaten sup- References Cited ported for rotational motion about the axisthereof; UNITED STATES PATENTS (b) a longitudlnal card clamp on theperiphery of said platen; 421,765 2 /1890 Rosback l97136X (c) lineindexing means including a line-spacing 10 687,000 11/1901 Barron 197136ratchet; 779,942 1/1905 Kavle 197 122 (d) a detent ring, having a detentnotch, coupled to 9271203 7/1909 w 197-136X said line-spacing ratchetfor rotation therewith; 980,689 1/1911 Smlth 197'114X (e) first andsecond detent rollers spring biased to re- 1,027,391 5/1912 Rabef197-414 main in contact with the periphery of said line-spac- 1513031879 5/1919 Gabrlelsqn 197-435 ing ratchet and said detent ring,respectively; 114951957 5/1924 KUTOYVSkI 197114 (f) adjusting means forrotating said detent ring re- 1,582,031 4/1926 Gabnelson 197136 lativeto said line-spacing ratchet, and about their 1,749,835 3/1930 197123common axis which is coincident with the said axis 119451894 2/1934Golng 197136 of said platen, to assure that said first detent roller2,023,507 12/1935 Belmer 197136 is engaged with said line-spacingratchet in a detent- 2272,0953 2/1942 197136 ing relationship when saidsecond detent roller is 2,841,264 7/1958 l f 197*123 engaged in saiddetent notch; and 3,122,931 3/1964 h s (g) coupling means forselectively engaging and dis- 3,208,575 9/1965 Emlg 197-123X engagingsaid line-spacing ratchet and said detent 35225387 12/1965 Beiderbeckeet 197-135X ring from said platen for unified rotation with said platenand to selectively adjust the angle between ERNEST WRIGHT Pnmary Exammersaid detent notch and said longitudinal card clamp to any predeterminedvalue. 2. The mechanism of claim 1, wherein said second detent roller iscarried at one end of a pivoted bell-crank

